1. Technical Field
The present invention is related to an apparatus for detecting a particle.
2. Description of the Related Art
Foreign particles, both organic and inorganic, in a plating solution cause defective plating of a substrate in a process of fabricating a printed circuit board. These foreign particles are introduced from the outside and/or generated within the plating solution, that is, generated by the break-down and/or coagulation of a plating additive. If it were possible to detect the presence and the size of foreign particles in real time, it would be possible to preclude the cause of the foreign particles and substantially lower the defective plating of the substrate.
In a widely known method of detecting a foreign particle in a solution, laser is irradiated into the solution in a plating tank, and the light dispersed by the foreign particle is collected to detect the foreign particle from the signal of the collected light.
However, in case it is difficult to permeate the laser beam into the solution, the detection is ether impossible or unreliable. Especially, since plating solutions are highly concentrated, it is difficult to permeate the red light, which is commonly used in commercial particle detectors, into the solution, making it difficult to detect a foreign particle reliably.
Moreover, since the permeability of laser beam is different for each different type of plating solution, the apparatus for detecting a foreign particle needs to be changed when a different plating solution is used.